treat multiple layers as one?

I want the ability to operate on multiple layers at once.  Is it possible?

It would simplify the duplication of hybrid surfaces (e.g. spiked surfaces).

I made some shaded lighting by overlapping 5 alpha layers.  I had to work with each layer individually.
It will be a symmetric CTF map, so that's 5 more layers that must be individually copied, flipped, and pasted.